The present invention relates to graphene synthesis via chemical vapor deposition (CVD) and, more particularly, to systems and methods for continuous single crystal growth of graphene.
Graphene is a single layer of carbon having a hexagonal bonding structure in a one-atom thick sheet. Graphene has a great potential in a wide range of applications from photovoltaics and electronics to desalination membranes. It has been demonstrated that graphene can be grown via CVD in multiple layers or as a single monocrystalline layer with the size of single crystals up to 1 cm. While 2-dimensional, single crystal materials, such as graphene, exhibit the potential for use in many applications, their performance is strongly affected by the quality of the material, with the single crystal form considered as the highest quality. Typically, 2-dimensional, single crystal materials are produced using epitaxial growth processes; however, this process requires single crystal substrates for deposition, which can be cost prohibitive. Moreover, epitaxial growth of graphene can be accompanied by difficult to control line defects due to more than one epitaxial adsorption geometry. Thus, despite the well-recognized potential of graphene single crystal layers, a reliable technology for the scaled up production of single crystal graphene remains a bottleneck in the transition from graphene research to the development of practically viable graphene devices that utilize single crystal graphene.
The performance of 2-dimensional, single crystal materials is greatly affected by the quality of the material and the best performance is typically observed when the material is defect free. That is why, despite recent advance in chemical vapor deposition (CVD) techniques, the standard quality comparison for 2-dimensional, single crystal materials still relies on microexfoliation methods that yield small amounts of high quality single crystal materials. The grain boundaries between single domains of graphene produced using typical CVD methods can compromise mechanical properties, chemical stability, electronic properties, and thermal conductivity of the material.
Thus, there remains a need for systems and methods for the scalable and cost-effective manufacture of single crystal graphene. In particular, there remains a need for a method of forming large single graphene crystals, particularly continuous single crystal graphene using inexpensive polycrystalline substrates.